Other data sets provided by CRISM but **not** of our interest are listed in the [Appendix](#CRISM-data-sets).
### MTRDR
Or simply MTR data, available at https://pds-geosciences.wustl.edu/mro/mro-m-crism-5-rdr-mptargeted-v1/mrocr_4001/. Directory `mtrdr` stores _science-data_, `browse` provides high-level data for quick exploration, and `index` provides the index (with information about the respective locations, for example) of all observations/products.
#### Projection
MTRDR data is projected in **Equirectangular planetocentric** projection of a sphere of radius **3394.839813316312 Km**, positive longitude **east**.
#### Timestamp
MTRDR data observation time -- `START_TIME` and `STOP_TIME`, are represented in **ISO** format, _e.g._, `2012-05-04T21:14:54.576`.
#### File naming convention
##### `BROWSE` directory
From `browse/browinfo.txt` (shortened for convenience):
> (MTRDR) browse products are organized in the appropriate BROWSE directory tree by year and day of year [...] with subdirectories for each observation identified by the class type and target ID.
>
> Three data files and one detached PDS label file describing the three files constitutes a single TER/MTRDR browse product set. The three data files are:
> - The .IMG file which stores the browse image as a 3-band 8-bit raw binary PDS image object.
> - The .HDR file which stores ENVI Header information associated with the IMG file.
> - The .PNG file which stores the 3-band 8-bit browse image in PNG format with an alpha transparency channel that corresponds to the non-scene edge pixels.
>
> The spatial dimensions of each PNG and IMG file match the spatial dimensions of the source MTRDR.
>
> [...]
>
> There are up to four browse products containing data derived from the VNIR detector, and up to thirteen browse products containing data derived from the IR detector. A single browse product (TAN) includes data from both detectors. A TER/MTRDR product set with sensor type J ("joined") has associated browse products from both detectors for a total of 18 products. A detailed description of the TER/MTRDR browse products is provided in the CRISM Data Product SIS.
>
> The file naming convention for the MTRDR browse products is as follows.
> WVnnn – Wavelength information for the I/F image / Macro #
> (A prefix of “BR” in the Activity portion of the filename identifies the file as a TER/MTRDR Browse Product, in which case it follows the naming convention specified in section 2.3.4.7.)
> - SensorID = J (for joined S and L)
> - Filetype =
> TER (Targeted Empirical Record)
> MTR (Map-projected Targeted Record – short for MTRDR)
> - version = 0, 1,...,9, a, ..., z
> - Ext =
> IMG - Image cube
> HDR - Associated ENVI header
> LBL - PDS label
_Addendum_ to file naming convention for MTRDRs:
> Activity =
> INnnn - Processing Information
### MRDR
MRDR data is split across 4 directories under https://pds-geosciences.wustl.edu/mro/mro-m-crism-5-rdr-multispectral-v1/: the first two, `3001/` and `3002/`, contain the first release of data produced using `version 2 of the radiometric calibration`, while `3101/` and `3102/` provide a reprocessed batch of `IF` and `DE` MRDRs using `"version 3 of the radiometric calibration"` (see [errata.txt][mrdr_errata]). The split in each data set, `xx01` and `xx02`, separate data according to their location on the Mars surface; `xx01` contain data from Mars regions MC01-MC15, as presented in the table below (form `crism_avsis.pdf`), while `xx02` contain data from regions M16-M30.
MRDR data is projected in **Equirectangular planetocentric** projection of a sphere of radius **3396 Km**, positive longitude **east**.
#### File naming convention
An MRDR (Figure 3-13) consists of several or more strips of multispectral survey data mosaicked into a map tile. Thus a map tile is constructed from a large number of TRDRs. The tile contains image data in units of I/F extracted from temporary TRDRs, plus Lambert albedo, summary products, and the DDR data used to generate them.
> An MRDR contains several files, each with a distinct label. The file naming convention for an MRDR is as follows:
> * Tile = Tnnnn, tile number with tile 0000 at the south pole, increasing sprialing northward
>
> * Product Type = "MRR" for MRDR
>
> * Subtype of product, e.g.
>
> IF – I/F
>
> AL – Lambert albedo
>
> SU – Summary Products
>
> DE – Derived Products for I/F
>
> DL – Derived Products for Lambert albedo
>
> WV – List of wavelengths and wavelength ranges of radiance and I/F images
>
> * CLat = nn, Planetocentric latitude of center of the tile
>
> * Hemisphere = #, N or S for north or south latitude
>
> * CLon = nnn, East longitude of center of the tile
>
> * Resolution = nnnn, in map-projected pixels per degree, e.g. 256 pixels per degree
>
> * version = 0, 1,..., 9, a,..., z
>
> * Ext = IMG or TAB
_An MRDR, as shown in Figure 3-13, contains up to five multiple-band images at 256 pixels/degree, and up to two list files._
#### Index files (directory contents)
Files in the Index Directory (Table 3-16) are provided to help the user locate products on this archive volume. The following files are contained in the Index Directory:
We start at the [PDS Geosciences Node] page for [MRO CRISM] data access.
## CRISM data sets
First thing to cover is the [Data Product Software Interface Specification].
MRO data sets address: https://pds-geosciences.wustl.edu/mro/
*[EDR](https://pds-geosciences.wustl.edu/mro/mro-m-crism-2-edr-v1/): VNIR and IR Experiment Data Records (_i.e._, "raw" data);
*[CDR](https://pds-geosciences.wustl.edu/mro/mro-m-crism-2-edr-v1/): calibration files used to process EDRs to units of radiance or I/F;
*[TRDR](https://pds-geosciences.wustl.edu/mro/mro-m-crism-3-rdr-targeted-v1/): VNIR and IR Targeted Reduced Data Records, calibrated data in non-resampled sensor space;
